Add Unique data from registration to First Post

Ok so I have a site. I created a registration page using gravity forms. Users fill out the form (Site url, user name, so on and so fourth). Upon submission a new blog is created for that user (using blog template plugin). I am looking for a way to auto create their first post based on information supplied during registration. Basically a hidden field is populated with some data that needs to be added to their fist post on their NEW blog. Is there any way to accomplish this that would not require extensive recoding?

Thank you for the help in advance